The broad aim of this research project is to compare the quality of health care provided by managed care plans and more traditional fee- for-service (FFS) plans. The specific hypothesis examined in this project is that there are quality differences between the two types of health coverage because FFS patients are treated by more experienced and sub-specialized physicians than are managed care patients. This hypothesis is tested in this pilot study by investigating the outcomes of a particular surgical procedure, hysterectomy. The data for the project come from the Case Mix and Charge Data collected by the Massachusetts Rate Setting Commission. An analysis of these data will provide (i) estimates of outcome differentials between FFS and managed care patients; and (ii) estimates of the proportion of any differential that is attributable to different skill levels of physicians treating FFS and managed care patients.